The present invention relates generally to a manual densitometer for measurement of the color composition of an original.
Manual meters are generally known, for example such as those in DE-A-40 27 805. This particular device, which is a device for measuring electrical values, can be adjusted to the respective measuring range by a flat disk that is moved manually. Indentations are also provided along the sides of the disk in order to facilitate operation of the flat disk.
In particular, manual densitometers today are widely used aids for measuring the color composition of an original. Such manual densitometers and the special parts of such manual densitometers are known, for example, from U.S. Pat. No. 3,846,027; from U.S. Pat. No. 4,968,140; from U.S. Pat. No. 4,961,646; or from U.S. Pat. No. 4,929,084. Such manual densitometers include a unit for measuring the original; the densitometers of the type disclosed in the patent specifications cited above have a measuring head, which can be extended out of its housing into a measuring position, whereupon it measures the color composition of the original either at a particular point or across a larger area. For example, the color density of the original can be measured for a certain color at a particular point or across a larger area. Selectable measurement variables (for example, the density) as well as specific parameters (for example, the special color whose density is measured) are depicted on a display unit; that is, they are visible to the user on a graphic display, for example with a menu of options on a small monitor, and they can be selected from the displayed menu by means of pushing the corresponding buttons, or other menus, such as sub-menus of the general menu, can be called up by pushing the correct buttons. In turn, once the variables and parameters to be measured have been selected, then the measurement process can be activated by pressing the appropriate buttons so that the measured values appear on the display after the measurement has taken place.
The manual densitometers described above are devices that function well, but there still is room for improvement. For example, activating the keyboard buttons for controlling the measurement process has the disadvantage that the speed with which the menus are run through by pressing the keyboard buttons (running up and dow the menu) is always tied to the same fixed reaction time at which the pressing of a button is convened into the corresponding change on the display unit. The user has no influence on this reaction time, namely the user cannot decrease this amount of time.
In addition, such a keyboard of buttons also has the disadvantage of being relatively bulky and of being difficult to operate by hand. In the case of such manual densitometers, it has to be noted that a user usually has to hold with one hand the original being measured, whereas the other hand is used to hold and operate the manual densitometer. This usually means, however, that whenever the user has to hold the densitometer in his hand, then he can only move his hand slightly. If the keyboard of buttons is relatively large, then it is all the more difficult to operate. Furthermore, the keyboard requires a relatively large amount of space, which is a rare commodity in hand-held devices.
User-friendly graphics are also well known in the computer field. In particular, the well-known mouse has proven to be particularly suitable as a pointer and control instrument. But because of the space problems mentioned above, it is not practical for hand-held equipment. The mouse operates with a two-dimensional "trackball", which converts the motion of the rotary ball into a corresponding movement of the mouse's pointer. This trackball, which is clearly superior to a keyboard for saving space, is already being used on its own as a select and control instrument in other devices for selecting certain parameters or functions. For example, such a trackball is used for selecting certain types of stitches in a sewing machine under the model name of "BERNINA 1530.RTM. Inspiration." But this sewing machine always has to be firmly positioned on a flat surface so that the user can easily move his hand in order to operate the trackball. But even then, this kind of trackball still has the disadvantage that the selected parameters can change easily with the slightest movement of the trackball, because a change in the position of the trackball, regardless of what direction it is, results in a corresponding change in the position of the pointer in the menu. As a result, the selection of individual options or parameters in the menu becomes more difficult because the precise command to call up the desired option or the desired parameters in the menu is made comparatively more difficult with the trackball.